Professional consensus on screening mammography after age 70 is lacking because comorbidities can complicate the decision of whether to screen elderly women for breast cancer. When practice guidelines are unclear, providers'values and patients'perceptions and beliefs may influence this decision making. OBJECTIVES/AIMS: 1) To identify the impact of comorbid conditions on mammography utilization, stage at diagnosis, treatment, and differences in survival among female Medicare beneficiaries over 65 years of age without a prior history of breast cancer. 2) Using clinical vignettes featuring women of different ages with different comorbidities, to identify physician and patient characteristics that influence physicians'decisions about mammography screening when practice guidelines are unclear. 3) To determine whether the effects of comorbid conditions, age, and race/ethnicity on mammographic screening among elderly women are related to their willingness to accept mammography and their perceptions of the associated benefits and barriers. METHODS: We propose to study the linked database of Medicare claims (information on mammography utilization and treatment of breast cancer) and the California Cancer Registry (information on stage at diagnosis, tumor size and other characteristics) to identify comorbid conditions among women aged 67 years or older who were newly diagnosed with invasive breast cancer in 1993 through 2002. A self- administered questionnaire and case vignettes will be mailed to a random sample of 600 physicians in metropolitan Sacramento. We will conduct 15-20 minute interviews of 150 female patients attending primary care clinics at UCDMC, within thirty days of an encounter.